1. Field of the Invention
The invention relates generally to video display devices and more particularly to an alignment apparatus for a video display device.
2. Description of the Prior Art
In the field of video display devices, each display device includes a plurality of structural plates and the precise alignment of these plates is of significant concern. In the prior art, the structural plates were joined together in an adjusted position. In the German patent No. DE-OS 29 52 528, a display device is disclosed in which electrons of a gas discharge are passed through selectively opened holes of a control structure into a plasma-free space where they absorb energy due to the presence of an accelerating voltage. The electrons finally produce dots of lights on a luminescent screen. The central structure includes several structural plates which are each perforated in a regular pattern and bear stripe electrodes. A screen is deposited on a screen plate and consists of phosphor stripes or dots. Each of these structures must be aligned in relation to one another so that the parts are joined together in the adjusted position. For alignment purposes, the screen plate includes adjustment studs which are accurately designed to size and onto which a spacing frame andother structural plates are stacked serially. The spacing frame and the strutural plates have close tolerance openings through which the adjusting studs pass. Additionally, each component part mounted in this manner is aligned visually in relation to a base and affixed provisionally in this position with a high temperature adhesive. The entire unit of structural plates was then soldered at elevated temperatures. However, the apparatus and method of stacking the structural plates is complicated because each screen plate bears precise adjusting studs. Furthermore, this adjustment system included a coarse and a fine adjustment and the adjustment procedure was rather complex and therefore not particularly suited for mass production. There remains a demand for a reliable adjustment apparatus and method suitable for mass production.